Why would my Switch BackSide-180 be much better than my Normal BackSide-180?

I believe I've practiced both the same amount, but for some reason, I've gotten the Switch BackSide-180 pretty much down, however, the Normal BackSide-180 seems to have me wash out and over-rotate a lot of the times. Even if I don't revert back to the normal direction, I tend to have to heel to feel balanced and then carve out to the side a bit rather than continue in a straight line.

Is this the usual progression most of you feel? What would be some of the causes? What should I look out for and try to correct?